<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
    <title></title>
    <link rel="stylesheet" href="imooc.css" type="text/css">
    <script src="http://libs.baidu.com/jquery/1.9.1/jquery.js"></script>
</head>

<body>
    <h2>可见性筛选选择器</h2>
    <h3>:visible/:hidden</h3>
    <div class="left">
      <div class="div">
          <a>display</a>
          <p id="div1" style="display:none;">display</p>
          <!--style="display:none;"不显示-->
      </div>
      <div class="div">
          <a>width</a>
          <a>height</a>
          <p id="div2" style="width:0px;height:0px;">width/height</p>
          <!--style="width:0;height:0"不显示-->
      </div>
      <div class="div">
          <a>visibility</a>
          <a>opacity</a>
          <p id="div3" style="visibility:hidden;opacity:0">visibility</p>
          <!--style="visibility:hidden;opacity:0"占位不显示-->
      </div>
    </div>

    <p id="show"></p>
    <script type="text/javascript">
    
      function show (ele) {
        if (ele instanceof jQuery) {
          $("#show").html('元素的长度的 = ' + ele.length)
        } else {
          alert(ele+' 不是jQuery对象')
        }
      }
    
    	//查找id = div1的DOM元素,是否可见
    	show($('#div1:visible'));

    	//查找id = div2的DOM元素,是否可见
    	show($('#div2:visible') );

    	//查找id = div3的DOM元素,是否可见
    	show($('#div3:visible'));
      
    	//查找id = div1的DOM元素,是否隐藏
    	show($('#div1:hidden'));

    	//查找id = div2的DOM元素,是否隐藏
    	show($('#div2:hidden'));

    	//查找id = div3的DOM元素,是否隐藏
    	show($('#div3:hidden'));
    </script>



</body>

</html>